Stitch-length control



Oct. 10,1950

A: AUSTLID STITCH-LENGTH common.

Filed Jan. 18, 194"! Faientecl Oct. 10, 1950 Arnljot Austlid, Oslo, Norway 1 Application J anuary 18, 1947, Serial No. 722,816 In Norway January 22, 1946 4 Claims.

The present invention relates to a device for adjusting the stitch-lengths of sewing machines. Said device is of the type which controls the displacement of turnable means such as the fabric mover or feeder and thus also stitch-length, by means of a tiltable arm, the end or outer positions of which corresponds to maximal stitchlength for the two directions of movement of the fabric or of the fabric mover respectively, the middle position of said arm corresponding to zero stitch-length. In the previously known devices of this kind the movements of the arm towards each side of its middle position is limited by an adjusting screw, the point of which engages the material of the sewing machine body, when the arm reaches one of its outermost positions. Thus such positions, and thereby also the stitch-length, may be adjusted for different values by adjustment of said screw.

However, such an arrangement does not provide for very fine adjustment possibilities, and especially not adjacent to the middle position of the arm. Now, for buttonholing and for embroidery work very short stitches are used, which means that the arm must, adjacent to its middle position, be adjusted very close to the same, at the one or the other side thereof, and it is important that fine adjustment of such short stitches in question could be effected.

It is an object of the invention to provide an arrangement enabling such fine adjustment.

Another object of the invention is to provide an arrangement enabling a very rapid shifting from short to long stitches, and vice versa.

Still a further object is to provide a device which automatically locks the adjusting screw in position for short stitches.

Other features of the invention will appear from the following description of a suitable embodiment illustrated in the accompanying drawing wherein: 1

Figures 1 and 2 illustrate the adjusting device, shown in two projections at right angle to each other, part of the machine body being shown in section.

Figure 3 illustrates, on a larger scale, thepoint of the adjusting screw in engagement with the recess provided in the machine body material; and

Figure 4 is a side view of a sewing machine equipped with the new adjusting device.

Control of the stitch-length is effected by adjusting the movement of the fabric mover by means of a pivotal or titltable arm 2 extending through a slot 3 in the material 4 of the machine body. Said arm 2 is provided with. a finger grip I. Arm 2 is tiltable in the directions of the arrows (Figure 2) into any one of its two outer positions, in which such tilting is stopped by engagement of the arm with any one of the end surfaces? of the slot 3. The connection between arm 2 and the fabric mover is so arranged, that the largest stitch-length is obtained when arm 2 isin any one of its outer positions, one such position serving for forward movement of the fabric and the other for rearward movement thereof. The

middle position shown in Figure 2 corresponds to stitch-length zero.

The stitch-length may be adjusted for different values thereof by means of an adjusting screw 5 provided with a knurled head or grip I and screwed into a sleeve or the like 8, attached at one side of the arm 2. Normall the adjusting screw 5 is situated parallel to the arm 2. The point 6 of the screw may be brought nearer to or farther from the machine body 4 by turning the knurled head. In this manner it is possible to adjust the uppermost and lowermost tilting positions of arm 2, as in these positions the screw point 6 will abut against the flat outer unrecessed face of the machine body 4; such abutment of the screw point 6 will occur prior to contact of the arm 2 with theend surfaces 3 of the slot 3, if the position of the screw 5 is properly adjusted.

When buttonholing or embroidery work is to be made very short stitch-lengths are used, and accordingly arm 2 must be situated very near to its middle position, at one or the other side of the, latter.

In this case, however, no sulficient control of the stitch-length is obtainable merely by making the point of the adjustment screw abutting against the unrecessed, surface of the ma;

chine body. According to the invention such fine adjust ment is made possible by the arrangement now to be described. In the material of, the machine body there is, in front of the point of the adjusting screw when arm 2 is in or about its middle] position, providing a recess ll, into which the point of the screw extends, when the screw is turned so that the point thereof is, located at or past the plane of machine body surface. The

end faces I2 of said recess ll, taken in the direction of tilting of arm 2, then form abutments for the point 6 and thus limit the tilting movements of said arm. In order that a very fine de-, gree of adjustment shall be obtainable said end faces l2 are oblique or sloping, so that the screw,

1n buttonholing it is important to be able to shift rapidly from making short to making long stitches, since it is desirable to use longer stitches near the ends of the buttonhole and to lock the seam by return sewing with the same stitch length as before. In order that the screw point 6 may be brought rapidly out of engagement with the recess l 1, without unscrewing the same, the sleeve 8 is pivotally attached to the arm 2 by means of a pivot stud 9. This pivot is situated at so short distance from the material of the machine body, that the adjustment screw may be moved out of engagement with the recess H by swinging the screw in the direction indicated by an arrow in Figure 2. The arm 2 thereafter may be tilted for obtaining great stitch-length. When then short stitch-length is again desired,

\ arm 2 is tilted back to middle position and the screw is swung back to the start position shown in Figure 2, so that the screw point 6 may again cooperate with the sloping surfaces l2. Screw 5 is secured in its starting position by means of an abutment it provided on arm 2.

My new stitch length controlling device is operated in the following manner:

If a fine adjusted short stitch length is desired, the screw 5 is turned in such position that its point 6 projects into the recess H, and abuts against one of its sloping surfaces 52. The exact point of contact between point '6 and sloping surface 12 can be adjusted by turning knob I so as to obtain the desired fine adjusted short stitch length.

If a longer stitch is desired, then the screw 5 is turned outward so that its point abuts against the fiat outer face of the body 4 somewhere between the edges of the recess II and the end of surfaces 3 of the slot 3. The exact point of contact between point 6 of the screw 5 and the flat outer face of the body 4 can be adjusted by turning knob 1 so as to obtain the desired medium stitch length.

If it is desired to obtain long stitches without adjustment by screw 5, it is possible to turn screw 5 upward about pivot stud 9 into a position substantially parallel to the outer face of the body 4 enabling free adjustment, i. e. free tilting of the arm 2. u If and when it is desired to again use screw 5 for adjustment purposes, the same is turned downward until it hits against the projecting abutment is provided on arm 2, ensuring that the screw is in properly adjusted operative position extending parallel to the arm 2.

My present invention relates to sewing machines and stitch-length controlling means of the general type disclosed in the German Patent No. 634,748 dated September 2, 1936. In such machines, a turnable member is provided in well known manner for adjusting the stitch length. This turnable member is operated, i. e. turned, by means of the arm 2 connected with the turnable memberin such a manner as to be adapted to turn it if the arm is moved by means of the grip I as described above.

It should be stressed that Fig. 1 shows a horizontal section through my adjusting device and Fig. 2 a vertical section so that the arm 2 is movable in a vertical plane as usual in such adjusting means.

As will be understood the details of the construction may be varied within the scope of the in-' 4 device comprising a tiltable arrn carrying an adjusting screw, the point of which adjusting screw engages the material of the machine body when the arm is in any one of its end tilting positions, the machine body having a recess in front of the adjusting screw when said tiltable arm is substantially in its middle position, the end surfaces of said recess forming sloping abutments for said screw point upon tilting of said arm, said adjusting screw being pivotally attached to said arm and adapted to be swung out of said recess without being unscrewed.

2. A sewing machine stitch-length controlling device comprising a tiltable arm carrying an adjusting screw, the point of which adjusting screw engages the material of the machine body when the arm is in any one of its end tilting positions, the machine body having a recess in front of the adjusting screw when said tiltable arm is substantially in its middle position, the end surfaces of said recess forming sloping abutments for said screw point upon tilting of said arm, said adjusting screw being pivotally attached to said arm at a point so near to the recess, that the screw may be swung out from the latter even when screwed into its innermost position.

3. A sewing machine stitch-length controlling device comprising a tiltable arm carrying an adjusting screw, the point of which adjusting screw engages the material of the machine body when the arm is in any one of its end tilting positions, the machine body having a recess in front of the adjusting screw when said tiltable arm is substantially in its middle position, the end surfaces of said recess forming sloping abutments for said screw point upon tilting of said'arm, said adjusting screw being pivotally attached to said arm and adapted to be swung out of said recess without being unscrewed, and an abutment on said arm serving as stopperfor the screw in the normal position thereof.

4. A stitch length controlling device for sewing machines provided with turnable means for adjusting the stitch length, said stitch length controlling device comprising in combination a slot in the body of said sewing machine; a tiltable arm passing through said slot and connectable at its inner end with said turnable means for adjusting the stitch length; an adjusting screw attached to the projecting portion of said tiltable arm in such a manner as to be adapted to abut with its tip against the outer face of said machine body; turning means on said adjusting screw for moving the same in a longitudinal direction so as to move its tip into a position abutting against the outer face of said machine body, whenever desired; a recess in the outer face of said machine body arranged so as to be located in front of said adjusting screw when said tiltable arm is located substantially in the middle of said slot; and sloping end surfaces connecting the opposite ends of said recess with the outer face of said machine body adapted to engage said tip of said adjusting screw.

ARNLJOT AUS'ILID.

REFERENCES CITED The following references are of record in the file of this patent:

FOREIGN PATENTS Number Country Date 314,696 Great Britain July 4, 1929 634,748 Germany Sept. 2, 1936 

